The North American Invasion of the Giant Resin Bee (Hymenoptera: Megachilidae)

The giant resin bee, Megachile sculpturalis Smith (Megachilidae: Megachilinae), is a species originally of Asia recently adventive in North America. This large and conspicuous species was first recorded at a few localities in the mid-Atlantic states of the United States, but is now found from southeastern Canada (Ontario) to Georgia, and as far west as western Pennsylvania and northwestern Alabama. Known occurrences of this species in its native distributional areas were used to generate an ecological niche model for the species, which can be used to anticipate the geographic potential for species in novel landscapes. The niche model was tested on the native range of the species for robustness in predicting independent suites of occurrence points. The niche model was then used to predict the potential distribution of M. sculpturalis in North America-our results indicate that this species has the potential eventually to occupy the entire eastern half of the continent, as far west as the Great Plains. The model also predicts that the species would find appropriate conditions along the Pacific Coast, in Mexico, and in the West Indies. Impacts of M. sculpturalis on native Megachile species are entirely unknown.